Tapering metal tubes



S. FINDLATER TAPERING VMETAL TUBES Filed sept. 8, 1944 3 Sheets-Sheet l mljalliwczllii Dec, E6, wir?, s. FINDLATER TAPERING METAL TUBES Filed Sept. 8, 1944 5 Sheets-Sheet 2 i nveidam" 5751/5/1/50/1/ A/ l e 315, B9497- s. FINDLATER 2,432,566

TAPERING METAL TUBES Filed sept. 8, 1944 's sneetsfsheet 5 oui-*rica TAPERING METAL TUBES Stevenson Findlater, Pittsburgh, Pa., assgn'orto National Tube Company, a corporation of New Jersey Application September 8, 1944, Serial No. 553,214

3 Claims.

This invention relates to a methodof and apparatus for tapering metal tubes and, more particularly, to a method of and apparatus for forming metal tubes having a, uniform outside diameter and a tapered inside diameter.

There frequently arises a need for tubes hav# ing a substantially uniform outside diameter but in which the walls taper in accordance with requirements of the use for which they are intended. Such an example may be found in the tubes 4employed for producing airplane propeller blades. A heavy wall in the base of such tubes is needed to provide suiiicient strength to accommodate the centripetalv forces while a lighter wall near the tip of the blade reduces the overall centrifugal force but supplies suiicient strength to meet the torsional requirements.

It is accordingly an object of the present invention to provide a method of forming metal tubes having a uniform outside diameter and a tapered inside diameter.

It is another object to .provide an apparatus for forming metal tubes having a uniform outside diameter and a tapered inside diameter. It is a further object to taper tubes uniformly in an expeditious manner.

The foregoing and further objects will be apparent from the specication and drawings wherein:

Figure 1 is a plan view of an embodiment of my invention;

Figure 2 is a side elevational view thereof;

Figure 3 is a longitudinal cross-sectional view of the tube gripping and turning mechanism shown at the left hand end of Figures 1 and 2;

Figures 4 and 5 are cross sections along lines IV-IV and V-V of Figure 3;

Figure 6 is a side elevation, partly in section, of the tube forming apparatus, showing a tube therein; and

Figure 7 is a cross section along lines VII-VII of Figure 2.

Referring more particularly to the drawings, the numeral 2v designates a base on which is pivotally mounted a iluid pressure cylinder 3 connected to lever 4 which is pivotally connected at its lower end to the base 2, and at its upper end i engages trunnions on collar member 6 carried by rotatable spindle 'I of a clamping and rotating device 8. The member 5 clamps a workpiece extending therethrough, moves it forwardly and rotates it a. partial revolution upon actuation of the iiuid pressure cylinder 3. The construction and operation of the clamping and rotating device 8 will be more fully described hereinafter.

A. iixed housing I0'is also carried by the base 2 and has a pair of -spaced parallel surfaces I I and I2 of the desired width, each of which carries a pair of racks I3. Surfaces II and I2 have a diverging portion I4 at the entry side thereof adjacent the clutch member 'I.

Disposed in the xed housing I0 is a roll housing I5 which carries a pair of backing up rolls IS in engagement with the surfaces II and I2, the rolls I6 having gears I8 keyedor otherwise secured to necks I'I thereof, which gears are in mesh with the racks I3. Interiorly disposed in the roll housing I5 between the backing up rolls I6 is a pair of working rolls 20 having substantially semi-circular grooves 22 therein of constant diameter forming a substantially circular pass therebetween. Gears 23 which are keyed or otherwise secured to necks 2l of the working rolls 20 are in engagement to key the rolls 20 together and also engage the gears I8. Necks I'I and 2l are journaled in bearing blocks 25, slidably mounted in roll housing I5, and are biased outwardly by spring 24 to keep the gears I8 in mesh with racks I2 anc1 |3 and also to open the -pass When'the roll housing is positioned between the diverging surfaces I4.

'I'he ends of a yoke 30 are connected to roll housing I5 by rods Sillon either side of the housing I0, and the center portion is connected to a piston rod 33 operated by an hydraulic cylinder 32 mounted on the baie 2. Thus, it is seen that admission of fluid under pressure to alternate ends of the cylinder 32 will reciprocate the roll housing I5 in stationary housing I0.

A tapered mandrel 35Yis disposed in the pass of the working rolls 20. The mandrel 35 is carried by a ball and socket joint 36 at the end of the housing I0 which permits rotation but not longitudinal movement thereof.

The rotatable spindle 'I of the clamping and rotating device 8 is slidably mounted in and keyed for rotation with a rotatable barrel 40 mounted in bearings 4I. Attached to the inner end of the spindle 'I are ,a pair of arms 42 connected to the mid-portion of toggles 43. The upper ends of the toggles 43 are pivotally connected to an in-l sert 44 slidably mounted in and keyed for rotation with the barrel 40. The lower ends of the toggles are connected to U-shaped frame members 45 in which is mounted a' jaw 46. A complementary jaw 4l is fixed to a stud-like portion 48 of the lower portion 49 of insert 44. Forward movement of the insert 44 and the jaws 48 and 41 carried thereby is opposed by springs 5U. Thus it is seen that forward movement of the spindle l by cylinshown).

der 3 acting through lever 4 and collar 6 to actuate the bars 42 pulls the upper jaw,46 into clamping engagement with a workpiece by toggles 43, since longitudinal movement of the inserts is opposed by the springs 50. After the jaw 46 firmly engages the workpiece, the reactive force of the springs 50 is overcome and continued movement of the spindle moves the workpiece forwardly. This closes a circuit to motor 52 mounted on frame 2 through contacts 5I and-.the motor is thereby energized to operate a predetermined amount controlled by a time-controlled relay (not Since the motor 52 hasa gear 53 in mesh with a ring gear 54 on the barrel 40, the workpiece is thereby rotated a predetermined amount. The cylinder 3 may then be reversed to open the toggles 43 and allow the springs 50 to return the insert 44 to its original position.

In operation, a tubular workpiece X is longitudinally moved by suitable conveyor means (not shown) through the collar 6 and member 8 between the rolls 20, which are spread apart at the entry end of the housing i0, and onto the tapered mandrel 35. The cylinder 3 is then operated to feed an increment of the workpiece forwardly by member 8, operation of which was hereinbefore described, onto the mandrel 35 and expand the outer end thereof due to its engagement with the tapering surfaces of the mandrel. The cylinder 32 is then operated to move the roll housing I in the housing I0 and thereby roll down the workpiece onto the mandrel, causing the metal ofthe tube to flow in the direction of the roll travel. As soon as the rolls 20 have reached the end of the workpiece, the direction of travel is reversed to bring the roll housing between the diverging surfaces I4 and cause the roils 20 to be ySpread apart by the springs 24. Another increment of the workpiece is then fed forwardly onto the mandrel 35 by actuation of the cylinder 3 operating the clamping and rotating device 8 which also causes a partial rotation of the workpiece. The cylinder 32 is again actuated to reciprocate the roll housing and the working rolls 20, and this sequence of operation is followed until a tapered workpiece of the desired length is obtained.

Thus, it is seen that a workpiece having a constant outside diameter which is determined by the semi-circular groove 22 in the rolls 20 anda tapered inside diameter corresponding to the taper on the mandrel 35 is obtained. The mandrel taper may be varied to form a varying interior configuration in the workpiece if desired.

While I have shown and described one specic embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other formsmay be devised within the scope of my invention, as dened in the appended claims.

I claim: i

1. Apparatus for forming metal tubes having a constant outside diameter and a tapered inside diameter which comprises a housing. a pair of spaced parallel trackways which diverge out.- wardly at the entry end of said housing, a tapered mandrel disposed intermediate said surfaces with the smaller end disposed between said diverging surfaces, a pair of rolls having a circular pass therebetween mounted between said surfaces, means to move said rolls longitudinally between said surfaces, means to spread said rolls apart when they are between said diverging surfaces' and means for advancing a tube onto said man..

drel and partially turning same- 2. Apparatus for forming metal tubes having a constant outside diameter and a tapered inside ldiameter which comprises a housing, a pair of rotated by said racks and gears, means to spread said rolls apart as they pass between said diverging surfaces, and means for advancing and partially turning a tube on said mandrel when said rolls are spaced apart at the entry end of said housing.

3. Apparatus for forming metal tubes'having a tapered inside diameter which comprises a ,housing, a pair of spaced parallel trackways which diverge outwardly at the entry end of said housing, a tapered mandrel disposed intermediate said surfaces with the smaller end disposed between said diverging surfaces, a pair of rolls having a metal working pass therebetween mounted between said surfaces, means to move said rolls longitudinally between said surfaces, means to spread said rolls apart when they are between said diverging surfaces, and means for advancing a tube onto said mandrelv and partially turning same.

STEVENSON FINDLATER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 185,374 Whitehouse Dec. 12, 1876 331,576 Tasker Dec. l., 1885 1,810,885 Neuberth June 16, 1931 2,161,065 Krause June 6, 1939 FOREIGN PATENTS Number Country Date 57,906 Germany July 29, 1891 521,611 Germany Mar. 27, 1931 

